1. Field of the Invention
The present invention relates to an optical connector plug that holds front ends of optical fibers and couples the optical fibers to each other.
2. Description of the Related Art
In the related art, optical coupling between optical fibers used for optical communication is performed using an optical connector. The optical connector includes optical connector plugs that hold front ends of optical fibers and an optical connector adapter that fix the optical connector plugs to each other and performs optical coupling of the optical fibers.
As the optical connector, an SC-type optical connector (complying with IEC 61754-4) that couples the optical fibers to each other using a ferrule barrel-shaped body (with the outer diameter of 2.5 mm) for holding the optical fibers or a miniaturized MU-type optical connector (complying with IEC 61754-6) using a ferrule barrel-shaped body (with the outer diameter of 1.25 mm) for holding the optical fibers is used.
In recent years, Fiber To The Home (FTTH) that establishes a high speed communication environment using access networks formed by using optical fibers and connecting subscriber lines from a telephone office to homes is spreading. In this optical fiber communication, an infrared ray with a wavelength of 1.3 μm to 1.55 μm is used as light for communication. Therefore, light output tends to increase.
However, if the high-output communication light is emitted from the front ends of the optical fibers and a human body, particularly, a part such as eyes, is exposed to the communication light, there is a high possibility of having a bad affect on the human body. In particular, a high safety is required for the optical connector plugs for holding the front ends of the optical fibers led into households according to the spread of the FTTH to the households.
From this requirement, a structure of an optical connector plug that incorporates a shutter to shield a front end face of the optical fiber is disclosed (for example, refer to Japanese Patent Application Laid-Open (JP-A) No. 2005-292777 (page 22, FIG. 26)). The optical connector plug that incorporates the shutter is inserted into an optical connector adapter 110, the shutter is opened, and the front end of the optical fiber is exposed, and the optical connector plug is coupled to the optical connector adaptor 110.
In the optical connector plug that is disclosed in JP-A No. 2005-292777, an inner barrel (shutter holding member) contacts a coupling claw of the optical connector adaptor, is pressed, and changes from an extension state to a reduction state. At this time, a shielding plate (shutter member) is pushed down by a moving plug frame, a front end face of a ferrule is exposed, and the optical connector plug is coupled to the optical connector adapter.
However, although the coupling claw of the optical connector adapter originally pushes the inner barrel (shutter holding member), deformation may be caused due to the pushing force, and the inner barrel (shutter holding member) may push the coupling claw and move to a center portion of the optical connector adaptor.
This is caused when the elastic force of the coupling claw of the optical connector adaptor is weak, when an interval of the facing coupling claws is more than a defined value, or when the optical connector plug is erroneously inserted with the inner barrel (shutter holding member).
As such, if the inner barrel (shutter holding member) moves to the center portion of the optical connector adaptor, the shielding plate (shutter member) is interposed between the ferrule and a sleeve holding member of the optical connector adaptor. In this state, if the optical connector plug is strongly inserted, the shielding plate (shutter member) is deformed or the shielding plate is damaged.
Even when a shape corresponding to the coupling claw of the optical connector adaptor does not exist like when the optical connector plug is connected to a measurer such as an optical power measurer and a ferule end face shape measurer or a ferrule end face cleaning tool is used, the shielding plate (shutter member) may be damaged.